REFINEMENT OF MAP POSITION OF THE HUMAN GLUR6 KAINATE RECEPTOR GENE (GRIK2) AND LACK OF ASSOCIATION AND LINKAGE WITH IDIOPATHIC GENERALIZEDEPILEPSIES

Hereditary factors play a major role in the etiology of idiopathic gen eralized epilepsies (IGEs). The pivotal function of glutamate receptor s (GluRs) in excitatory neurotransmission implicates their involvement in epileptogenesis and genetic susceptibility to IGEs. A trinucleotid e repeat polymorphism detected in the 3' untranslated region of the ka inate-selective GluR6 receptor gene (GRIK2) on chromosome 6 makes it p ossible to perform linkage and association studies with this high-rank ing candidate gene. The present study tested the hypothesis that allel ic variants of GRIK2 contribute to the genetic susceptibility to the c ommon IGEs. Linkage and association analyses were conducted in 63 fami lies ascertained through IGE patients with juvenile myoclonic epilepsy , juvenile absence epilepsy, or childhood absence epilepsy. Our linkag e and association results suggest that allelic variants of GRIK2 are n ot involved in the expression of the common familial IGEs, and radiati on hybrid mapping assigns GRIK2 to the chromosomal region 6q16.3-q21. This localization excludes GRIK2 as a candidate for the putative IGE s usceptibility locus ''EJM1'' on the short arm of chromosome 6.